Diffusion battery penetration

The experimental diffusion battery penetration, g-s, is related to the theoretically calculated penetration probability, Pj C<1) by... 

The count median diameter, d, and the geometric standard deviation, Og, were calculated by using the experimental diffusion battery penetration values, gj, as input for a computer program based on the optimization procedure described earlier (Busigin et al., 1980). 

The penetration probability of a particle passing through the diffusion battery is given by (Busigin et al., 1980)... 

The penetration constants a and b for parallel plate diffusion batteries are ... 

The activity size distributions were determined from the calculated penetration values in the diffusion batteries using the method outlined for aerosol size measurement (equation (6) for RnWL and equations (8) and (9) for 222Pb concentration). 

Scheibel, H.G. and J. Porstendorfer, Penetration Measurements for Tube and Screen Type Diffusion Battery in Ultrafine Particle Size Range, J. Aerosol Sci. 15 673-679 (1984). 

For the diffusion battery of Prob. 8, determine the maximum particle diameter which can be collected with 50 percent efficiency with a total flow through the unit of 1 L/min. For penetration use Eq. A-l in Fig. 10.4. 

Diffusion diameter Diffusion battery Air is passed through a long, narrow tube as laminar flow small particles diffuse to and stick to wall larger particles penetrate further longitudinally along tube size distribution is obtained by inverting distance distribution +... 

Several published works have been devoted to the mathematical solution of the problems of penetration of aerosols through a diffusion battery, which is essentially a bundle of identical circular or rectangular channels in parallel [11]. The deposited matter is characterized only by its diffusion coefficient it means that the derived formulae hold for aerosol particulates, as well as for molecular entities. 

The theory of diffusion through the screens in diffusion batteries, as described by a semi-empirical equation derived by Cheng and Yeh (1980) correlating the screen fractional efficiency with experimental parameters, does not strongly differ from that formulated by Thomas and Hinchliffe (1972) as the penetration of particles through the screen (or the screen collection efficiency) is also an exponential function of the above parameters. 

In the diffusion battery, the gaseous ions are sorbed by the wall of the diffusion tube while en route through it, analogous to the removal of aerosol particles by the battery wall. The fraction penetrating the battery, F, is given by the equation (Townsend, 1900)... 

For the determination of the free fraction the attached and the total radon daughter activity concentration were measured. The separation of the free radon daughters from the total daughter concentration was carried out by means of a high-volume diffusion screen battery (Reineking and Porstendorfer, 1986) with a 50 % penetration efficiency for 4 nm particles and for a flowrate of 2.4 m h-1. ... 

---